1. Field of the Invention
An apparatus consistent with the present invention relates to a two-axis actuator and, more particularly, to an X-Y stage micro-actuator for a data storing system that uses a Scanning Probe Microscope (SPM) technique.
2. Description of the Related Art
A data storing system which uses a Scanning Probe Microscope (SPM) technique includes a medium for information storage; an actuator for moving a stage, on which the medium is mounted, in two axes (ex., X and Y directions); one or more probes, each having a tip for storing information on the medium or reading information from the medium; and a signal processing unit for processing storing and reading signals.
The multi-probes can write or read multiple pieces of information at the same time and require that the tip of the multi-probe approach the medium. Therefore, the multi-probe needs an actuator and a sensor. The actuator deforms the multi-probe in a direction (ex., a Z direction) so that the tip of the multi-probe can approach the medium. The sensor reads information from the medium by sensing the deformation of the probe according to the information on the medium.
In order to move along two axes (or more than two axes) such as in the X and Y directions, an actuator requires at least three electrodes for unidirectional movement along each axis and at least five electrodes for bidirectional actuation along each axis. According to U.S. Pat. No. 5,536,988, two-axis actuation can be achieved by forming the actuator that requires multiple electrodes in one silicon structure via a thermal oxidation insulating method. This method solves the insulating problem among the electrodes in a two-axis actuation structure, but this method requires a very complicated process.
In order to solve this problem, a single stage micro-actuator capable of moving along two axes using only one electrode was disclosed in U.S. Pat. No. 6,445,107.
However, the stage in the above patent is inefficient because the stage, for locating a medium, is formed on the same plane as the actuating part for generating an electrostatic force. Thus, the information storage capacity is decreased due to a limited stage area.